Technical Abstract:
The value of Sucraid enzyme supplements for correction of sucrase deficiency in CSID is well documented. Sucraid is an invertase derived from brewer’s yeast which has been characterized as hydrolyzing sucrose to glucose and fructose. However, sacrosidase may have another role: conversion of fructose to glucose. Patients with known duodenal mucosal activities participated in oral breath tests using 20 mg of UL-13C labeled substrates and periodic 13CO2 breath enrichment analyses normalized for % of glucose oxidation (CGO%) as previously reported (JPGN 2009;48:412–8). Patients were supplemented with 22 drops of Sucraid by mouth at zero. The presenting patient had a history consistent with CSID responsive to Sucraid but surprisingly all disaccharidase activities were normal. While in the hospital, the child had acute abdominal pain after an evening snack of crushed pineapple. Because of the Sucraid clinical benefit a 13C-sucrose BT was performed; the unsupplemented test was low normal (CGO 116%) and the Sucraid supplemented normal (134%). Dietary history was reviewed and fructose elimination diet prescribed. There was a clinical response to the fructose elimination diet and the girl was restudied after 2 months. The 13C-sucrose BTwas again low normal (CGO 129 %) and rose to normal (162%) with Sucraid supplementation. This BT was repeated with 13C-fructose BT; the baseline was CGO 108% and rose to 125% with Sucraid. The specificity of the 13C-fructose test was evaluated in a control patient with CSID; 13C-sucrose BT increased from 58% to 118% and 13C-fructose from 132% increased to 152% CGO with the enzyme supplement. Fructose malabsorption can be confirmed with 13C-fructose BT. The in vivo response of fructose absorption to Sucraid is likely due to the intrinsic invertase activity of the enzyme which may convert excess luminal fructose to absorbable glucose.